In a conversation with a reporter on NBC News last November, in which Trump had been challenged on his claim that that he'd seen video of Muslims in America "celebrating" after the 9/11 World Trade Centre attacks, he said: "I have the world's greatest memory. It's one thing everyone agrees on."

And in a recent speech in which Trump criticised the Obama administration as being "stupid" he said: "I went to an Ivy League school. I’m very highly educated. I know words. I have the best words.”

This second comment was this week turned against Trump in an attack made by the right wing American Future Fund: